algebra precalculus - If a certain number is divided by the sum of its two digits, how to find it from quotient and remainder?

If a certain number is divided by the sum of its two digits, the quotient is $7$ and the remainder is $3$. If the digits are reversed and the resulting number is divided by the sum of the digits, the quotient is $3$ and remainder is $7$. Find the number.

My Attempt:

Let the number be $10x+y$.

According to question:

$$\dfrac {10x+y}{x+y}=??$$ .

I could not get how to make the equation using quotient and remainder. Please help.

Answer

HINT:

$$10x+y=7(x+y)+3=7x+7y+3$$

and $$10y+x=3(x+y)+7=3x+3y+7$$
Can you proceed now?